DayPicker

DayPicker is the lower-level day-grid subsystem used by the calendar stack.

Labeling

The surrounding calendar surface should explain what month and year the user is currently viewing.

AnnouncementFocus the demo and press a key from the table.

Key	Action
`←→`	Moves the focus to the previous or next day, wrapping to the neighbouring week and skipping disabled days. In RTL the arrows are mirrored: ← moves to the next day.
`↑↓`	Moves the focus to the same weekday of the previous or next week, stopping at the edge of the month.
`HomeEnd`	Moves the focus to the first or last day of the week.
`Ctrl + HomeCtrl + End`	Moves the focus to the first or last day of the month.
`Page UpPage Down`	Moves the focus to the same weekday in the first or last week of the month. The month itself does not change: paging months belongs to Calendar.
`EnterSpace`	Selects the focused day.

Every row is checked in a real browser: Playwright presses the key in Chromium and checks where the focus and the active item land.

Keyboard navigation is inherited from DataGridPicker and the grid item semantics.

Without defaultActive, the tab stop is today when it is in the visible month, otherwise the first selected day in it, otherwise its first day; when you change month later, pass active / onChangeActive to keep the tab stop in view
Focus and active cell behavior should remain visible across selected, excluded, and disabled dates.

Grid roles and state semantics come from the underlying picker/grid primitives.
Weekday labels and period labels should stay synchronized with the rendered month.